Fan assembly

ABSTRACT

A fan assembly ( 10 ) includes a housing ( 20 ) with an air inlet ( 70 ), a fan inlet ( 60 ), and an air outlet ( 80 ). The fan assembly further includes an impeller ( 30 ) and a motor ( 40 ) configured to drive the impeller, the impeller having a plurality of circumferentially positioned spaced blades ( 34 ). An air-permeable guard ( 50 ) is positioned between the air inlet and the fan inlet to prevent users from touching the impeller ( 30 ), and is spaced a first distance ( 54 ) from the fan inlet ( 60 ), and a second distance from the air inlet ( 70 ) so that a filter ( 90 ) may be provided between the air inlet ( 70 ) and the air-permeable guard ( 50 ). Preferably, the first distance ( 54 ) is such so as to allow incoming air to at least partially rotate prior to entering the fan inlet. Preferably, the plurality of circumferentially positioned spaced blades ( 34 ) is positioned circumferentially around a domed center ( 32 ) of the impeller ( 30 ), the domed center ( 32 ) facing the fan inlet ( 60 ), and the domed center ( 32 ) co-rotates with the spaced blades ( 34 ).

FIELD OF THE INVENTION

The present disclosure is directed generally to a fan assembly that improves efficiency and lowers power consumption.

BACKGROUND OF THE INVENTION

Fresh, clean air is one of the most basic needs for human beings. However, air can contain many different kinds of impurities, including particulates, viruses, bacteria, and fungi, all of which can cause or aggravate health issues, illness, and other negative outcomes. In order to improve air quality, there are many different technologies that clean air, the most common of which is an air filter. In general, filters clean air by means of a fan that pushes and/or pulls the air through the filter unit.

In order to push or pull air through an air filter in an air purifying unit there are several different fan types, including radial fans and axial fans. Axial fans generate high flowrates, but result in relatively low maximum pressures. In contrast, radial fans generate relatively high maximum pressures but have relatively low maximum flowrates. A commonly utilized type of fan is the forward curved radial fan. Compared to a backward curved radial fan, the forward curved fan is intended for higher maximum flow rates and lower maximum pressures. Additionally, a forward curved radial fan has the advantage of high performance with minimal sound, which is an important feature for air purifiers. In contrast, however, there is high consumer demand for high flow rates and a small fan/appliance volume. Essentially, consumers want smaller fans with higher output and lower energy consumption. These two needs, however, are in direct conflict.

In order to provide an energy-efficient system that reduces the volume of the appliance, it is necessary to reduce the pressure drop in the flow of air in the appliance. The main causes of the pressure drop are the air being forced through the filters, as well as the location and configuration of the air inlet to the fan. Current air purifiers, for example, are designed to have an air-permeable grid or guard positioned in the inlet to the fan. The air-permeable grid or guard prevents consumers from touching the impeller with their fingers. Unfortunately, this configuration has several disadvantages, including that there is a drop in pressure as the air flows through the inlet.

SUMMARY OF THE INVENTION

Accordingly, there is a need in the art for a fan housing and impeller design that prevents the unwanted drop in pressure. The invention is defined by the independent claims. The dependent claims define advantageous embodiments.

The present disclosure is directed to inventive methods and apparatus for a fan and impeller configuration. Various embodiments and implementations herein are directed to a fan assembly that increases efficiency and lowers power consumption. Generally, in one aspect, a fan assembly comprises a housing with an air inlet, a fan inlet, and an air outlet; and an impeller comprising a plurality of circumferentially positioned spaced blades, and a motor configured to drive the impeller. The fan assembly has an air-permeable guard which is positioned between the air inlet and the fan inlet to prevent users from touching the impeller. The air-permeable guard is spaced a first distance from the fan inlet, and a second distance from the air inlet so that a filter may be provided between the air inlet and the air-permeable guard. Using the various embodiments and implementations herein, the fan assembly reduces the drop in pressure experienced by air as it enters the impeller region as a result of the larger cross-sectional area that the air-permeable guard may have if it is not confined to the area available for the relatively small fan inlet because it is placed at the first distance from the fan inlet. The fan assembly preferably also allows air to have a rotational component as it enters the air inlet and impeller region.

Applicant has further recognized that the prior art inlet configuration limits the rotational component of the air before it encounters the region of the fan blades, thereby limiting the performance of the fan in terms of maximum pressure as well as maximum flow. By positioning the air-permeable guard at a predetermined distance from the fan inlet, in an embodiment, the incoming air is allowed to at least partially rotate prior to entering the fan inlet. This results in a significant improvement in fan performance.

According to a preferred embodiment, the plurality of circumferentially positioned spaced blades is positioned circumferentially around a domed center of the impeller, the domed center facing the fan inlet, and wherein the domed center co-rotates with the spaced blades. This will reduce resistance for the airflow, as the air can rotate with the rotating center of the dome, which results in an increased efficiency.

According to an embodiment, each of the plurality of circumferentially positioned spaced blades is curved. This results in a higher performance.

According to an embodiment, the domed center of the impeller has a plurality of spokes. This results in less noise.

According to an embodiment, the maximum height of the domed center is approximately 1 to 75% of the maximum height of the impeller. According to another embodiment the maximum height of the domed center is approximately 1 to 60% of the maximum height of the impeller, and according to yet another embodiment the maximum height of the domed center is approximately 1 to 50% of the maximum height of the impeller. If the dome is higher, air will bump on the dome thereby increasing resistance and reducing performance. The dome is present to provide room for the motor.

According to an embodiment, the maximum width of the domed center is approximately 20 to 95% of the maximum width of the impeller.

According to an embodiment, the housing includes two or more air inlets. This allows for an increased filter surface, and a higher inflow.

According to an embodiment, the air-permeable guard comprises a grid.

According to an embodiment, the diameter of the fan inlet is approximately 50 to 100% of the diameter of the impeller. A larger diameter disturbs the air flow and will result in increased noise, while a smaller diameter impedes the air flow.

According to an embodiment, the predetermined distance between the air-permeable guard and the fan inlet is approximately 2 to 80 mm, and can be 2 to 30 mm.

According to an embodiment, the air-permeable guard is spaced a predetermined distance from the air inlet. This provides room for the filter.

According to an embodiment, the motor is positioned on a side of the impeller facing away from the fan inlet.

These and other aspects of the invention will be apparent from and elucidated with reference to the embodiment(s) described hereinafter.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings, like reference characters generally refer to the same parts throughout the different views. Also, the drawings are not necessarily to scale, emphasis instead generally being placed upon illustrating the principles of the invention.

FIG. 1 is a cross-sectional view of a fan assembly in accordance with an embodiment.

FIG. 2 is a grid formation for an air-permeable guard in accordance with an embodiment.

FIG. 3 is a cross-sectional view of an impeller in accordance with an embodiment.

FIG. 4 is a top view of an impeller in accordance with an embodiment.

FIG. 5 is an exploded view of a fan assembly in accordance with an embodiment.

FIG. 6 shows an advantageous shape of a volute in the impeller housing to optimally guide the air flow.

FIG. 7 shows an embodiment in which the plates in the air outlet are aligned with the air flow.

DETAILED DESCRIPTION OF EMBODIMENTS

The present disclosure describes various embodiments of apparatus, systems, devices, and methods for improving the function of a fan assembly. More generally, applicant has recognized and appreciated that it would be beneficial to improve efficiency and reduce power consumption of a fan during operation. A particular goal of utilization of embodiments of the present disclosure is to be able to increase the output of a fan assembly without increasing power consumption.

In view of the foregoing, various embodiments and implementations are directed to a fan assembly with an air-permeable guard positioned between the air inlet and the fan inlet, and spaced a predetermined distance from the fan inlet to allow the incoming air to at least partially rotate prior to entering the fan inlet. The fan assembly also has a radial impeller with a plurality of spaced blades positioned circumferentially around a domed center that faces the fan inlet.

Referring to FIG. 1, in one embodiment, a fan assembly 10 is provided that includes a housing 20, an impeller 30, and a motor 40. The housing 20 can be a variety of shapes, sizes, and materials. For example, housing 20 can be made of plastic, metal, or a combination thereof, among other materials. Housing 20 can be small to enclose a smaller impeller design, or can be larger to accommodate an industrial-sized impeller. The fan assembly 10 may be in a horizontal position facing upward, or the fan assembly can face downward. The fan assembly can alternatively be positioned in a vertical position, a tilted position, and a wide variety of other positions.

Housing 20 also includes a fan inlet 60, an air inlet 70 and an air outlet 80. The fan and air inlets are sized and/or shaped to allow air to enter from the environment and engage with the impeller 30. Accordingly, the fan and air inlets can be round, square, or any of a wide variety of shapes. Further, housing 20 can include two or more air inlets 70, and/or two or more fan inlets 60. Air inlet 70 can be open or can include a grid, mesh, netting, or other covering such as a visually-appealing covering. According to an embodiment, fan inlet is open to allow maximal air flow into the impeller region. According to an embodiment, air inlet and/or fan inlet are circular, with a diameter in the range of approximately 50-100% of the diameter of impeller 30, and preferably in the range of approximately 65-90% of the impeller diameter. The distance from the fan inlet 60 to the impeller can be, for example, smaller than 0.03×D, preferably 0.02×D, where “D” is the diameter of the impeller, although a variety of distances are possible.

Having an open fan inlet allows air passing into and through the fan inlet to at least partially rotate before encountering the impeller, which results in a significant increase in fan efficiency. However, if both fan inlet 60 and air inlet 70 are open, a user may be able to directly access the impeller 30 which can interfere with the functioning of the fan or which can lead to injury to the user. Therefore, fan assembly 10 also includes an air-permeable guard 50 positioned between air inlet 70 and fan inlet 60. According to an embodiment, air-permeable guard 50 is a grid, mesh, net, or similar design that maximizes air flow while simultaneously preventing fingers or other body parts from entering the fan inlet and encountering the impeller and/or motor.

According to an embodiment, the air-permeable guard 50 includes sufficient number and/or size of openings to allow for maximum air flow. As shown in FIG. 2, for example, an embodiment of the air-permeable guard 50 is viewed from above and has a height “z” and a width “y” such that the total area of the guard is “z”×“y”, although other configurations are possible. Similarly, each of the openings can include a height “l” and a width “m,” where “l” and “m” are dimensioned to prevent a finger or other body part from passing through the opening. For example, “l” and “m” can be in the range of approximately 4-18 mm and more preferably they are in the range of approximately 6-15 mm. The value of “l” and “m” can be different. Air flow through the air-permeable guard 50 can be defined as the ratio of the area allowing air flow (“l”×“m”× the number of openings) over the total area of the guard (“z”×“y”). According to an embodiment, the ratio is approximately 30-90%, and preferably in the range of approximately 50-75%. Although the air-permeable guard 50 is shown as square in FIG. 2, the guard can be any of a variety of shapes including rectangular, circular, and many others. As an example, the guard components can be rounded on the leading edge and pointed on the trailing edge to maximize air flow, among many other configurations. Further, although the openings in FIG. 2 are all preferably substantially similar (i.e. equally sized and equally distributed), the openings can be constructed to have two or more different sizes and/or shapes in the same guard. Bars of the guard 50 should be rounded at front side, with a rounding radius of bars ≧0.5 mm. Bars at back side (fan side) may be sharp, but are preferably rounded. The guard should have a permeability of ≧65-70% (based on surface area of 292×372 mm) with the holes uniformly distributed. The hole sizing should pass the finger safety test.

In contrast to prior art configurations in which air-permeable guard 50 often forms all or part of the fan inlet 60 itself, according to the present invention, the air-permeable guard 50 is separate from and spaced a predetermined distance 54 from fan inlet 60, as shown in FIG. 1. In a preferred embodiment, this predetermined spacing allows the air that has passed through the air-permeable guard 50 to at least partially rotate before entering the fan inlet encountering the impeller, which results in a significant increase in fan efficiency. According to an embodiment, the air-permeable guard 50 is separate from, and spaced a predetermined distance 52 from a filter 90. Predetermined distance 52 and predetermined distance 54 can be identical or can be different, with either distance 52 or distance 54 being greater. Further, one or more of predetermined distance 52 and predetermined distance 54 can be adjustable.

According to an embodiment, predetermined distance 52 is approximately 0 to 80 mm, and preferably is approximately 2 to 10 mm. However, a wide variety of distances is possible and can be dependent on a number of factors including the size of the housing, the desired air flow, and many others. According to an embodiment, predetermined distance 54 is approximately 2 to 80 mm, and preferably is approximately 2 to 30 mm. However, a wide variety of distances is possible and can be dependent on a number of factors including the size of the housing, the desired air flow, and many others. Preferably, distance 54 is approximately 15 to 25 mm, preferably at least 18 mm to allow the air to rotate and thus reduce resistance and increase performance. A distance exceeding 25 mm appears to unnecessarily increase the size of the fan assembly. In a vacuum cleaner application, a distance 54 between 2 and 10 mm may suffice.

For an air filtration device, for example, the filter 90 is designed to remove and/or neutralize particulates in the air, including but not limited to viruses, bacteria, and/or fungi. There can also be multiple filters along the air flow path to increase filtration. The two or more filters can provide different functioning and/or can be designed to filter different particulates from the air. According to an embodiment, the filter can also be designed to remove and/or neutralize odors or gasses. According to the embodiment in FIG. 1, filter 90 is placed at some point between the air inlet 70 and air-permeable guard 50. In one vacuum cleaner application, the filter 90 would be directly adjacent to the air-permeable guard 50, and an air inlet formed by an inlet grille would be put at the other side of the filter 90.

Impeller 30 can be any type of impeller, including but not limited to a radial impeller and an axial impeller. If the impeller is a radial impeller, for example, it could be a forward curved or backward curved impeller. The impeller can be a wide variety of sizes depending in part on the size of the housing and/or the intended use or location of the fan assembly. According to an embodiment, shown in FIG. 3, impeller 30 is a radial impeller with a plurality of spaced blades 34 positioned circumferentially around a center point which is attached to motor 40. In the embodiment in FIG. 3, each of the spaced blades is attached to the body of the impeller at the bottom of the blade to form a basket-like impeller design. The impeller can be any of a variety of other shapes, with the blades 34 only attached at the top or bottom, or an alternating design. The blades 34 can be curved forward or curved backward, or can be a mixture of directions. In an axial design, for example, the blades will extend outward from a center 32 of the impeller, and can be curved in a number of directions.

Impeller 30 can include a center 32 that is domed, with the apex of center 32 of the dome facing the direction of the incoming air. The center can have a solid construction, or can include spokes 31 such as those depicted in FIG. 4 in order to reduce the sound radiated from the back of the fan. According to an embodiment, the center 32, such as the spokes in FIG. 4, are of matching design each with a smooth curve. According to an embodiment such as that depicted in FIG. 1, the impeller has a maximum height 36 that is defined by the blades 34. The domed center, in turn, has a maximum height 38 that can be equal to or less than maximum height 36 of the impeller. According to an embodiment, the height 38 of domed center 32 of the impeller is between approximately 1-100% of height 36 of the impeller, and is preferably in the range of approximately 1 to 75% of impeller height 36. According to another embodiment, maximum height 38 of domed center 32 is approximately 1 to 60% of maximum height 36 of the impeller, and preferably the maximum height of the domed center is approximately 1 to 50% of the maximum height of the impeller.

Further, according to an embodiment and as shown in FIG. 4, the impeller has a maximum width 35 that is defined by the outermost reach of the most distantly spaced blades 34. The impeller center 32 also has a maximum width 37 that is less than maximum width 35. According to an embodiment, the width of center 32 is between approximately 1-99% of maximum width 37, and is preferably in the range of approximately 20-95% of maximum width 37. Both the height and width of impeller 30 and center 32 can be designed or predetermined to maximize rotational speed and/or air flow, as well as to minimize noise, among many other design goals. According to an embodiment, the center 32 of impeller 30 co-rotates with the blades of the impeller. In embodiments where the fan inlet is positioned above the impeller, air pulled into the impeller region will first encounter the center of the impeller or the space just above the center of the impeller. A co-rotating center causes the entering air to have a rotational component, which improves efficiency of the fan. This effect is even more pronounced in the embodiment of the fan assembly where the center 32 of impeller 30 is domed.

Motor 40 is any motor or drive sufficient to cause a desired rotation of the impeller 30. According to an embodiment, motor 40 includes a drive shaft that attaches to the impeller at a point near the axis of rotation of the impeller. The motor can also be connected to the impeller indirectly, such as through a coupling element. Motor 40 can operate at a single rotational speed, or can operate at a variety of different speeds. Motor 40 may also include operation profiles that slowly increase or decrease rotation speed, that provide predetermined variable speeds, or other variations. As shown in FIG. 1, for example, motor 40 can be positioned entirely on the side of the impeller facing away from the fan inlet 60, which prevents the motor from interfering with air flow within the fan. However, other configurations of the impeller and the motor are possible.

FIG. 5 is an exploded view of an embodiment of fan assembly 10. The fan assembly includes housing 20 which defines an air outlet 80. The air outlet can be positioned, for example, in the direction of the air flow within the housing. The housing can be, for example, in one or more components, such as the impeller housing 22 shown in FIG. 5. The fan assembly also includes impeller 30 and motor 40 to drive the impeller. Behind the motor 40, the housing is closed. Following the flow of air from the exterior to the impeller, the fan assembly includes air inlet 70 having a width of at least 2 cm between a front plate and the housing, filter 90, air-permeable guard 50, and fan inlet 60. As shown by the configuration of air inlet 70 in FIG. 5, air can enter from multiple sides or directions in order to maximize air flow into the system. Preferably, the intake at air inlet 70 has no sharp corners and no (sharp) bends. Preferably, the fan inlet 60 is rounded over its thickness completely, at least at the side facing the air inlet, so as to reduce resistance. The impeller housing 22 is preferably dimensioned such that the distance fan inlet fan ≦5.0 mm, and more preferably ≦3.0 mm. The minimum distance fan blades−volute is preferably about 16 mm.

As shown in more detail in FIG. 6, the impeller housing 22 has a volute V surrounding the impeller 30, and shaped such that the air flow is optimally guided so as to again reduce unnecessary resistance. To this end, part V1 of volute V is tangential to the fan blades of impeller 30, and a second part V2 of the volute V is aligned with the air flow. While in the embodiment shown in FIG. 6, the impeller bottom is closed, the impeller preferably has spokes as shown in FIGS. 3 and 4.

As shown in more detail in FIG. 7, plate-shaped bars 82 in the air outlet 80 should angle with the air flow F so as to again reduce unnecessary resistance. The bars in outlet are preferably rounded at least at the side inside the appliance with a rounding radius of at least 0.5 mm.

It should be noted that the above-mentioned embodiments illustrate rather than limit the invention, and that those skilled in the art will be able to design many alternative embodiments without departing from the scope of the appended claims. In the claims, any reference signs placed between parentheses shall not be construed as limiting the claim. The word “comprising” does not exclude the presence of elements or steps other than those listed in a claim. The word “a” or “an” preceding an element does not exclude the presence of a plurality of such elements. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. 

1. A fan assembly comprising: a housing comprising an air inlet, a fan inlet, and an air outlet; an impeller between the fan inlet and the air outlet the impeller comprising a plurality of circumferentially positioned spaced blades; a motor configured to drive the impeller; an air-permeable guard positioned between the air inlet and the fan inlet to prevent users from touching the impeller, wherein the air-permeable guard is spaced a first distance from the fan inlet, and a second distance from the air inlet, the air-permeable guard having a larger cross-sectional area than a cross-sectional area of the fan inlet, and a filter between the air inlet and the air-permeable guard, the filter having a larger cross-sectional area than the cross-sectional area of the fan inlet, wherein an air flow path between the filter and the fan inlet has a substantially same cross-sectional area that is larger than the cross-sectional area of the fan inlet over a distance that is a least 15 mm.
 2. The fan assembly of claim 1, wherein the first distance is configured to allow incoming air to at least partially rotate prior to entering the fan inlet.
 3. The fan assembly of claim 1, wherein the plurality of circumferentially positioned spaced blades is positioned circumferentially around a domed center of the impeller, the domed center facing the fan inlet, and wherein the domed center co-rotates with the spaced blades.
 4. The fan assembly according to claim 3, wherein the domed center of the impeller comprises a plurality of spokes.
 5. The fan assembly according to claim 3, wherein a maximum height of the domed center is approximately 1 to 75% of a maximum height of the impeller.
 6. The fan assembly according to claim 3, wherein a maximum width of the domed center is approximately 20 to 95% of a maximum width of the impeller.
 7. The fan assembly according to claim 1, wherein the first distance is at least 15 mm.
 8. The fan assembly according to claim 1, wherein the first distance is smaller than 25 mm.
 9. The fan assembly according to claim 1, comprising an impeller housing having a volute (V) surrounding the impeller, and having a part (V1) towards the air outlet that is tangential to fan blades of the impeller
 30. 10. The fan assembly according to claim 1, wherein the air outlet has plates that are aligned with an air flow (F). 